The present invention relates to a sewing machine equipped with a needle threader having a threading hook which catches a thread led near to the thread eye of a needle and passes the thread through the thread eye and more specifically, it relates to a sewing machine with an automatic threader capable of drawing a thread drawn out from a thread supply and threaded through a thread take-up lever near to the thread eye of the needle simply by pressing an operating member, catching the thread with a threading hook inserted in the thread eye and waiting, and passing the thread through the thread eye with the threading hook.
The sewing operation of a sewing machine requires preparatory work, in which a thread wound on a spool is pulled out, is passed through a thread tension regulator, a thread take-up lever, a take-up spring and other members in a predetermined sequence and via a predetermined path, and is passed through the thread eye of a needle. Every type of sewing machines requires such threading work, not excepting the sewing machine equipped with a needle threader having a so-called threading hook.
A needle threader having a threading hook, suitably employed in recent sewing machines is merely capable of facilitating only the work for passing a thread through the thread eye of a needle and is incapable of omitting or facilitating the above-mentioned preparatory work for passing an upper thread through the thread tension regulator, the thread take-up lever and the take-up spring. Threading a sewing machine via a predetermined threading path is troublesome work even for a person skilled in operating the sewing machine and inexperienced operators are liable to fail to thread the sewing machine correctly. If the sewing machine is threaded incorrectly, the sewing machine is unable to carry out sewing operation even if the thread is passed through the thread eye of the the needle. Accordingly, it is important to thread the sewing machine correctly and reliably.
An automatic threader for a sewing machine invented by the applicant of the present invention is disclosed in Japanese Provisional Patent Publication No. 95095/84. This disclosed invention is capable of threading a thread pulled out from an upper thread supply to a take-up spring and passing the thread through the thread eye of a needle, and hence the invention is worthy of a high evaluation in this regard. This previously proposed automatic threader, however, requires a first operation for extending the thread downward from the thread take-up lever and a second operation for leading the thread near to a threading hook inserted in the thread eye of a needle, which is not desirable from the viewpoint of the facility of operation. Furthermore, the automatic threader has a sophisticated mechanism for extending the thread and is inferior in functional reliability.